Reducing current via photoconductor

Hello,

For a small project, I need to keep current inversely related to a photoconductor's conductivity. In other words, current can flow in the circuit when the photoconductor is *not* conducting. Note that the voltage and current is coming from a different part of the circuit, like a capacitor or battery. My last plan was to connect a zener diode to it so that when the current is high enough, the diode would reverse it's permitted direction of flow and therefore stop the current. When light is not shining on the photoconductor, it resists enough to drop the current below the level of the breakdown current.

Then I found out that zener diodes work via voltage, not current. So I still need to find a way. I understand it's possible by using a couple of transistors, but I'm not sure how. So, how would I go about either A) using transistors to solve my problem, or B) using another way?

Thanks, Bill

Reply to
Bill Wayne
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What exactly is the project?

I am working on something that sounds similar to what you are working on.

Reply to
kturnbull66

I'm working on a coilgun. I'm trying to use a light tripwire by setting up the circuit so that when a photodiode isn't getting any light, the circuit completes. It's a little more complex than that, so the capacitors used for the gun aren't going to be running through the photodiode (or anything else that can't withstand huge voltages/ currents).

Bill

Reply to
Bill Wayne

You must be dreaming if you think *anyone* can figure out what the hell kind of circuit you're talking about. Just skip your idea of abstraction, Einstein, and tell us more specifically about how and what you have hooked up and what it's supposed to do.

Reply to
Fred Bloggs

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